Black-and-white developer for photographic reversal processes



7 activity.

United States Patent A 6 Claims. (Cl.9655) The invention relates to a blackand-white developer for the first development step of photographic reversal materials, more especially color reversal materials.

In the processing of photographic reversal materials, quite special requirements are necessary for the black-and- Whitedeveloper for the first development step. These requirements generally are not fulfilled by known developers which are used for developing usual black-andwhite materials, so that new developers had to be discovered for the reversal process, more especially of color reversal materials. Thus, black-and-white developers which are intended to be used for the process under discussion may only contain a relatively small quantity of sulphites, since the dissolving of silver chloride by the action of these compounds is to be avoided. Developer substances which are widely used for normal black-andwhite development show disadvantageous eflects in connection with the present process, more especially when processing color reversal papers, and these efiects prevent their use in photographic reversal processes. For instance hydroquinone, for so far unexplained reasons, causes a non-uniform color formation in larger image areas having the same color.

Developers for the reversal process which contain 3-pyrazolidones as developer substance have already been described. However, such developers have no practical utility, since their low developing activity permits the utilization of only a small or minor portion of the actual sensitivity of the photographic emulsions being used.

We now have found that developer compositions which contain 3-pyrazolidones and o-phenylene diamine as developer substances are excellently suitable for the first black-and-white development of photographic reversal materials, in particular of color reversal papers. Due

to the presence of the o-phenylene diamine, the developing activity of the 3-pyrazolidones is considerably increased, so that with identical silver halide emulsions, a substantially higher sensitivity is achieved. The discovery according to the invention was all the more surprising,

in that it was found that m-phenylene diamine and H p-phenylene diamine only cause a slight increase in o-Phenylene diamines which are substituted on the nucleus are also suitable for the developer composition according to the invention, but these generally produce a substantially smaller efiect than the unsubstituted compound. Suitable substituents are, for example, lower alkyl having up to 5 carbon atoms, lower alkoxy groups having up to 5 carbon atoms, halogen atoms such as chlorine or carboxyl groups which can be esterilied with a lower aliphatic alcohol having up to 5 carbon atoms. o-Phenylene diamine by itself at a pH of about 10.0 does not develop any silver halide.

A particular advantage is offered by the combination of 3-pyrazolidones with o-phenylene diamine, when processing color reversal materials which contain a silver bromide emulsion as well as silver chloride emulsions in the several layers. The different types of emulsion layers are developed to equal extents.

For the reproduction of saturated color tones, it is of particular advantage that the first reversal developer according to the invention only forms photographically inactive oxidation products.

For the developer combinations according to the invention, it is possible to use the known developer substances of the 3-pyrazolidone series. Particularly suitable are pyrazolidones of the following general formula:

in which R is a hydrogen atom, an alkyl group containing up to 4 carbon atoms or a phenyl group which can be substituted, for example, by chlorine, lower alkyl groups such as methyl or ethyl, and also lower alkoxy groups such as methoxy, amino, acylamino, for example, acetamino or hydroxy; and R to R represent hydrogen, alkyl radicals containing up to 4 carbon atoms or phenyl radicals.

The following compounds exhibit particular utility 1-phenyl-3-pyrazolidone 5 -phenyl-3 -pyrazolidone 5-methyl-3-pyrazolidone 1-p-chlorphenyl-3 -pyrazolidone 1-phenyl-5-phenyl-3-pyrazolidone l-phenyl-5-methyl-3-pyrazolidone l-acetaminophenyl-3-pyrazolidone The substances are all known per se and are, for example, described in the article by J. D. Kendall, Brit. J. phot. (1951) 5 39. The concentration ratio between 3-pyrazolidone and o-phenylenediamine can vary within wide limits and can be adapted by means of a few preliminary tests to the requirements of the special copying process or to the properties of the color reversal material which is used.

Generally speaking, these two substances are used in a ratio from 60:40 to 40:60. According to one preferred embodiment, the two substances are used in approximately equal ratios, from 55:45 to 45:55. The aqueous developer composition according to the invention contain in dissolved form between 2-10 g., preferably 46 g.', per liter of each of the developing agents according to the invention, preferably o-phenylenediamine and l-phenyl- 3-pyrazolidone. The developer composition has a pH value of between 8.5 to 11.5, preferably between 10 to 11.

The developer combination according to the invention is in principle independent of the nature of the photographic color material. The color couplers can be incorporated into the emulsion layer in a dissolved diflusion-resistant form. According to another method the color coupler is first dissolved in an oily organic material and this combination is then dispersed in a finely divided state throughout the emulsion. The developer according to the invention can also be used in those reversal processes in which the so-called Successive Colorant Formation is applied. In this process the color coupler is incorporated into the color-forming developer composition. The successive color formation in each of the single layers of a multilayer material is obtained by controlled penetration of the processing solution. For example, in an integral tripack it is possible by means of a loaded dye coupling developer to develop the top layer of the material without affecting the lower emulsion layers if the time of development is carefully controlled. The developers according to the invention can also contain the usual additions of stabilizers, antioxidants, valkalizing substances, etc.

Experiment.-A photographic material on a film support containing 3 g. of silver in the form of silver bromide and 0.1 g. of silver developing nuclei per square meter of film was treated with a soda-alkaline solution of ophenylene diamine without having been exposed to light. No blackening of the sheet was observed. This shows that no silver bromide was dissolved by the o-phenylenediamine because any dissolved silver bromide would be reduced at the development nuclei which would result in the blackening of the material.

Example 1 A multi-layer material on a paper support, containing a silver bromide layer with 3-(p-stearoylamino'benzoylacetamino) isophthalic acid as yellow coupler, as well as two silver chloride layers with 1 (3 sulpho 4- phenoxy) phenyl 3 heptadecyl 5 pyrazolone as magenta coupler and N octadecyl 1 hydroxy 4- sulpho 2 naphthamide as cyan coupler, is exposed and developed at a pH value of 10.0 for 4-5 minutes at 20 C. in a first reversal developer having the following composition:

Grams Sodium hexametaphosphate 3 Anhydrous sodium sulphite 15 o-Phenylene diamine 5 Anhydrous sodium carbonate 60 Potassium bromide 5 1-phenyl-3-pyrazolidone 5 Benztriazlole 0.05

Made up with water to 1 liter.

After rinsing, the material is subsequently exposed in dilfused light and developed for 8 minutes in the following color developer:

Grams Sodium hexametaphosphate 2 Hydroxylamine sulphate 4 Anhydrous sodium sulphite 4 Potassium bromide 1 Anhydrous potassium carbonate 100 N-butyl-N-4-sulphobutyl-phenylene diamine 5 The material is then rinsed and bleached in a bleachfixing bath, as described, for example, in German Patent No. 866,605. The material is rinsed again and, after treatment with a hardening stop bath containing formalin, it is dried.

If development is carried out for 56 minutes in a developer having the following composition and a pH value of 10.0:

Grams Sodium hexametaphosphate 3 Anhydrous sodium sulphite 15 Anhydrous sodium carbonate 60 Potassium bromide 5 1-phenyl-3-pyrazolidone 5 Benztriazole 0.05

Made up with water to .1 liter, and if processing takes place as described above, then as compared with the first.

developer hereinbefo-re referred to, a substantially lower Utilization of the actual sensitivity of the photographic material is obtained, which requires a 3-4times increase in "the exposure time. i

If development is carried out for 56 minutes in a 'developer having the following composition and a pH "value of 10.0:

Grams Sodium hexametaphosphate Anhydrous sodium sulphite 15 o-Phenylene diamine 5 Anhydrous sodium carbonate 60 Potassium bromide 5 Benztriazole 0.05

Made up with water to 1 liter and if processing takes place as described above,vthere is obtained a black sheet 4 which means o-phenylene diamine has no developing capacity in this process.

Example 2 Black-and-white photographic reversal paper is exposed to the object to be reproduced and developed in the following first developer at a pH value of 10.0 for 5-6 minutes at 20 C.

Grams Sodium hexametaphosphate 3 Anhydrous sodium sulphite 20 o-Phenylene diamine 6 Anhydrous sodium carbonate 50 Potassium bromide 4 1-phenyl-3-pyrazolidone 6 Benztriazole 0.03

Made up with water to 1 liter.

The paper is rinsed and bleached for 5 minutes with:

Potassium dichromate g 5 Concentrated sulphuric acid cc 5 Made up with water to 1 liter.

After another rinsing, it is treated in the clearing bath with 50 g. of sodium sulphite per liter. It is then subsequently exposed with diffused light and developed in a second developer of the following composition:

. Grams N-methyl-p-aminophenol 1 Anhydrous sodium sulphite 13 Hydroquinone 3 Anhydrous sodium carbonate 26 Potassium bromide 1 This is followed by rinsing, fixing and the final rinsing. On developing in a developer, consisting of:

Grams Sodium hexametaphosphate 3 Anhydrous sodium sulphite 2O Anhydrous sodium carbonate 50 Potassium bromide 4 1-phenyl-3-pyrazolidone 6 Benztriazole 0.03

at 20 C. and for 5-6 minutes and having a pH value of 10.0 and processing as indicated above, a substantially lower utilization of the actual sensitivity of the photographic material is obtained as compared with the aforementioned first developer.

If development is carried out for 56 minutes in a developer having the following composition and a pH made up with water to 1 liter and if processing takes place as described above, there is obtained a black sheet which means o-phenylene diamine has no developing capacity in this process.

It will be clear to those skilled in this art that the practice of the invention lends itself readily to a number of useful modifications. For example, the aqueous developer composition may contain in addition to the developing agents the other ingredients of a typical developing solution such as preservatives or anti-oxidants for instant alkali-metal sulfites or bisulfites in particular sodium sulfite or hydroxylamine; alkalis such as alkalimetal carbonates, borates or phosphates especially sodium carbonate; restrainers or antifo-gging agents such as p0- tassium bromide or benzotriazole or derivatives thereot; calcium precipitants or sequestering agents to prevent precipitation in hard water such as sodium tetraphosphate, ethylenediaminetetraacetic acid and the like.

We claim:

1. A photographic reversal black-and-white silver halide developer formulation having sodium sulfite in a proportion low enough to avoid dissolving silver halide from a silver halide emulsion, o-phenylene diamine, a 3- pyrazolidone in which the 1, 4 and 5 positions can be substituted by phenyl or alkyl of up to 4 carbons, and sufficient alkalizing agent to give the developer at pH between 8.5 and 11.5, the o-phenylene diamine and the 3-pyrazolidone being in the ratio of from 60:40 to 40:60.

2. The combination of claim 1 in which the 3-pyrazolidone is 1-phenyl-3-pyrazolidone.

3. In a process for the production of a photographic black-and-white reversal image which comprises (a) exposing a light-sensitive silver halide photographic material to an object to be reproduced;

(b) developing the exposed photographic material in a first aqueous developing composition containing a black-and-white developer;

() rinsing the developed photographic material with water;

((1) bleaching the rinsed and developed material in an acid aqueous bleaching bath containing an alkalimetal dichromate as bleaching agent;

(e) rinsing the bleached material with water;

(f) treating the rinsed and bleached material with an aqueous solution of an alkali-metal sulfite;

(g) thereafter subjecting the material to a non-imagewise uniform exposure to actinic radiation;

(h) developing the thus exposed material in a second aqueous developing composition containing a blackand-white developer, and

(i) thereafter fixing the photographic material, the improvement according to which developing step (b) is effected with the developer formulation of claim 1.

4. A process as defined in claim 3 wherein said 3- pyrazolidone is l-phenyl-3-pyrazolidone.

6 5. In a process for the production of a photographic color-reversal image which comprises (a) exposing a light-sensitive silver halide photographic multi-layer material to an object to be reproduced; (b) developing the exposed photographic material in an aqueous developing composition containing a black-an-d-White developer; (c) rinsing the developed photographic material with water; ((1) subjecting the rinsed and developed material to a non-imagewise uniform exposure to actinic radiation; (e) developing the thus exposed material in the presence of color couplers in an aqueous developing composition containing a color-forming developer, the oxidation products of which are capable of reacting with said color coupler to form a dye, and (f) thereafter bleaching and fixing the photographic material; the improvement according to which developing step (b) is effected with the developer formulation of claim 1.

6. A process as defined in claim 5 wherein the 3- pyrazolidone is l phenyl-3-pyrazolidone.

References Cited by the Examiner UNITED STATES PATENTS 2,981,623 4/1961 Burgardt et al 9666 3,021,212 2/ 1962 King 96-66 FOREIGN PATENTS 768,071 2/1957 Great Britain.

OTHER REFERENCES Kendall, I. D.: Phenidone: A New Commercial Developing Agent. Brit. J. Photography, vol. 100, January 30, 1953, pp. 56-57.

The Focal Encyclopedia of Photography, London, The Focal Press, 1958, vol. II, pp. 984-985.

NORMAN G. TORCHIN, Primary Examiner.

C. E. DAVIS, Assistant Examiner. 

1. A PHOTOGRAPHIC REVERSAL BLACK-AND-WHITE SILVER HALIDE DEVELOPER FORMULATION HAVING SODIUM SULFITE IN A PROPORTION LOW ENOUGH TO AVOID DISSOLVING SILVER HALIDE FROM A SILVER HALIDE EMULSION, O-PHENYLENE DIAMINE, A 3PYRAZOLIDONE IN WHICH THE 1,4 AND 5 POSITIONS CAN BE SUBSTITUTED BY PHENYL OR ALKYL OF UP TO 4 CARBON, AND SUFFICIENT ALKALIZING AGENT TO GIVE THE DEVELOPER A PH BETWEEN 8.5 AND 11.5, THE O-PHENYLENE DIAMINE AND THE 3-PYRAZOLIDONE BEING IN THE RATIO OF FROM 60:40 TO 40:60. 